Renal and Urine Clearance Flashcards Preview

Physiology Renal ABS 2018 > Renal and Urine Clearance > Flashcards

Flashcards in Renal and Urine Clearance Deck (26):
1

What is the normal filtration rate? normal range?

GFR 125 ml/min; 100-125 ml/min -- 160-190 L/day; 180 L/day

2

What is in our filtrate? What's not filtered List them.

Anything freely filtered
glucose
amino acids
NO filtered-
Cells
Proteins

3

Equation for Excretion.

E=F-R+S

4

What is filtered load?

FL= GFR x {Plasma]x

5

What is the excretion rate?

E= Ux x V

where.. Ux= urine concentration of a substance
V= flow rate of urine

6

What is clearance?

The volume of plasma that is cleared of substance by the kidneys per unit time.

7

How do you calculate clearance?

C= Ux x Vx/ Px

8

How are GFR and NFP related?

GFR= NFP x Kf
kf= constant- surface area of nephrons/ amount of nephrons

9

Clearance > GFR...?

Filter and Secrete.
No reabsorption

10

Clearance = GFR...?

ONLY Filter
- USE Inulin to calculate GFR

11

Clearance < GFR...?

Filter and Reabsorb.
No Secretion

12

What is the best way to measure GFR? is it the only way?

1. INULIN- requires many steps- but most accurate way
2. NO- we can also use Creatinine- BUT it is a little of an overestimation- and a small portion is actually secreted- but it is easier to calculate

13

What is creatinine?

It comes from the breakdown of muscle (muscle metabolism)
- Creatinine levels do not really change

14

What is the relationship between GFR and plasma creatinine levels?

A decrease in GFR % can cause an increase in Plasma creatinine levels

GFR= 1/Plasma creatinine

15

What is a quick test to check for creatinine levels?

GFR= 1/Plasma creatinine

16

Normal Creatinine levels?

1 mg/dl AKA 1mg/100ml

17

What is the mass principle for what comes in and out of the kidney?

Artery= Vein + Ureters
Kidney(in)= Kidney (out)

18

What is PAH? Why is it important?

1. ParaAminoHipuric Acid - is NOT endogenous, but it is ONLY filtered and SECRETED.
It is so highly secreted that it enters the renal artery- and will be
a. excreted ONLY in urine
b. NO PAH will come out of the vein

19

What enters the Renal artery exits where?

The Ureters (all secreted, and therefore excreted!)

20

How do we calculate RPF?

RPF= Clearance of PAH
- because PAH is HIGHLY secreted
RFP= U(PAH)/ P(PAH) x V

21

What is a normal RPF?

600 ml/min

22

What does Clearance of Inulin tell us?

GFR

23

What does Clearance PAH tell us?

RPF

24

2 ways to calculate GFR?

1. Clearance of inulin
2. Clearance of Creatinine

25

How do you calculate filtration fraction? What is it?

FF= GFR/ RPF
It is a ratio of GFR and RPF- it tells us how much of what enters the kidney will actually be filtered
AKA a ratio of what is filtered/ total blood flow

26

How do you calculate RBF?

RBF= RPF/ 1- hematocrit